docs: def get_reference_line_marker_pattern(pattern):
      """Return a list of compiled regex patterns used to search for the first
         reference line in a full-text document.
         The line is considered to start with either: [1] or {1}
         The line is considered to start with : 1. or 2. or 3. etc
         The line is considered to start with : 1 or 2 etc (just a number)
         @return: (list) of compiled regex patterns.
      """
      return re.compile(u'(?P<mark>' + pattern + u')', re.I | re.UNICODE)